- Flare
- Soft in the corners
- not possible to add an UV or polarizer filter

comment:

I have only tested the lens with my Sony A-300.
The Minolta lens is sharper. When set to f8, sharpness is ok, f11 is better. Don't expect miracles.
DXO Optics supports this lens, it corrects the distortion and the light falloff in the corners.

Overall this is not an overly sharp lens but then ultra wides never come close to macro sharpness (to put it in perspective I only gave the CZ16-35 a rating of 4), it has similar centre sharpness to the minolta/tamron 17-35mm but softer in the corners. While it's the least sharp of the lenses I've compared it to the difference is not huge, buy this lens for types of shots it lets you take, it's those which give this lens the WOW factor. Equally don't go selling off this lens and expecting a huge jump in image quality short of going for the CZ.

Flare control is much better than I had expected better than the 20/24mm primes. The distortion control of this lens is amazing (especially at the long end) better than any of the other lenses I've compared it to.

Great lens, just what you'd expect for this focal length. Its perfect FOR WHAT IT IS, but nowhere near a prime or a dedicated wide zoom. This is an ultra wide designed to be used as such. Its not a 17-35.

negative:

lots of highlight skewing and haze when things are bright. Wish it had some more contrasty color...

comment:

I don't know what I paid but I do know this lens paid for itself quickly. There are a ton shots it avails but you have to know how to use it.

- Incredible distortion control (I still don't quite understand how it does it)
- Light
- Amazingly wide on FF

negative:

- not the sharpest tool in the box (but not as bad as some say)
- Lens ID comes through saying it's a minolta 28-85!

comment:

If you're looking for a wide angle lens for full frame then this is the lens to go for. Unbelievably wide and handles distortion so very very well. Fun walk around lens for metropolitan areas. The extra 5mm may not sound a lot moving from the KM17-35 but it makes a massive difference. It's not the sharpest lens, but to be honest it's pretty bloody good. If you're using it on FF you've got to be pixel peeping to see.

It's also important to remember DoF is from the subject to the sensor; a lens like this needs to be put right up to the object you're taking so unless that object is concave, one part of that object will be very close to the sensor and the rest won't be. While it may still be soft in the corners, often this is due to the shallow DoF.

If you're on crop sensor (anything except A850 or A900) but *might* move FF in future I'd recommend getting this. Will be wide enough for most stuff and is then useable on FF (the tamron 10-24 is a good lens, but not compatible with FF).

Thoroughly recommend, but if you are going to get into wide angle stuff, do some research on how best to use them. This is the best article you can read, and you really should read it:
www.kenrockwell.com/tech/how-to-use-ultra-wide-lenses.htm

This lens is great to use, without it you always wish you could just go a fraction wider because if you went back any further you'd fall into the sea/lake/road/railway line/doorway or shrubby bush.

There's a bit of distortion as with any UWA, you have to admire the control on it though at such angles. Flare is an issue because it can be hard to get the sun or other light source out of the frame, thats not a fault of the lens though! It's a bit like saying the lens is faulty because you have your feet in the shot.

I like this lens. It has better sharpness, contrast and colours than the Sigma 10-20 lens for APS-C sensors. Its not as sharp at 24 mm as the Minolta 24-50 - significantly !
This is an optical compromise - overall sharpness has been evened out which means it never gets critically sharp in the centre but this brings up (the stopped down) corner sharpness to an acceptable level. Its great for architecture but for landscape big enlargements would start to suffer. It WILL be heavy.
Sigma have eliminated CA and minimised linear distortion in an incredibly wide and versatile lens. Its an architecture lens primarily. They have done an excellent job with optical tradeoffs.

Not very sharp
Bulging front element (necessary compromise)
No filters

comment:

I am very happy with this lens. I think it is very good overall, and amazing in terms of distortion control.

To be honest, though, it has serious drawbacks as well -- which I think are understandable physical compromises given how wide it is. But you should understand the shortcomings or else you may be sorely disappointed. For me, the most disappointing aspect is that the lens is not very sharp at all. It's not horribly soft; it's fine. But even stopped down pretty far, it's not what I would call sharp.

If I could justify the expense, I might have gone with the CZ 16-35. But this "compromise" lens has the advantage of being significantly wider!

The view is just amazing on full frame. The sharpness of this lense is ok. I am kind of spoiled by the CZ 24-70's sharpness. The corners on this lense get very good once stopped down past F8.

Build quality is good, the typical Sigma EX DG build. I don't really like the feel of it though. The lense is light which is a plus but I would have liked a bit better build.

Also, this might only apply to my used copy but the focal length zoom is stiffer in the 12 mm and 24 mm end and smoother in the middle.

My biggest gripe for this lense is the ability for filters. I don't see any practical way to attach a ND filter to this lense. I might be able to hold the filter infront but I don't think there is a way to attach it for use at 12 mm.

I am very with this lense, for an ultrawide (12 mm!!!), the optics of this lense is just phenomenal. Sigma did a goos job on this lense!

12mm on FF (122°)
Very good distortion control
Sharpness is good on APS-C
Center sharpness is ok on FF

negative:

Flare - Flare - Flare!
Fullformat: Very soft corners at all aperatures!
(I have 3 copys over the years)

comment:

I like this lens - I use it with APS-C and also with FF.

The 12-24 delivers good image quality with 122°. The colour
reproduction is very natural and pictures with the 12-24 show a distinguished colour palette that invites you to step into the picture and marvel at the quality of reproduction and the depth of perspective.

The lens is sharp enough at f4,5-f5,6 in the center, but not the borders and corners! You have to stop down to f8 for good and f11 for corner to corner sharpness on APS-C. My point of view is that you need f14 for optimal sharpness on the FF Chip. I see minor limits of defraction at f11 to f16.

I often use this lens for architecture and landscape shots.
With f14 you have the hyperfocal DOF. You need experience to take shots when the sun is in the "field" - the lens catch flare very easely. Sometimes you can block the sun with your hands.

The distortion control is excellent for a zoom lens.

The mechanical quality is good: the mechanism of internal
focusing is indeed incredibly smooth in its movement.

The 12-24 is a very fine tool for the photographer
who wants to create pictures with a very strong visual
impact and a wide dimensional scope.

Recommend for Full Frame and APS-C users
if you can find a good sample.

i bought this lens cause i wanted to play with wide angle shots[ landscapes , buildings and interior ]
along the way i found out that there are many creative ways to enjoy this lens. makes models legs look longer , pets can get big heads etc etc still playing a lot with it.

Overall I am very happy with this lens. You need to stop it down a bit and expose to the higher end, in order to ensure a perfectly sharp image. But if handled with such care, you get perfect results. Pro Level. And this all the way to 12 mm !!!!
The CZ 16-35 might be a slightly better lens, but the focal length of the Sigma makes it for me the clear winner.

IQ is good and great around f/8-f/11. Wide opened, it vignettes like crazy.

I guess that the question is "how does it compare to the CZ?". This is the wrong question, they are lenses for very different uses. in a nutshell: the CZ has better micro-contrast and way better colors. The CZ can be used in dim light. This lens is much, much wider. Don't be fooled: 4mm is a lot of difference.

Colors are poor, noticeably yellow. Nothing which can't be corrected in post though.

I´ve now used this lens for some time, it´s not the fastest I own, that´s an understatement, but that´s not really what you buy it for. The super wide angle is! The whole range virtually without distortion, that´s already very impressive. I don´t mind I cannot put a polarizer in front of it (using the ´lenscap´ for that is not really an option imo, especially not at 12mm): colors are so saturated, so warm, it´s like it has been built in... The Sony kit-lens above does not come anywhere near of this lens in any terms, except of course weight and price, I think that´s as fair a statement as any.

Compared to my beloved 20-40 (which I carried by default on the α100) where they overlap, this lens beats it all the way, although I seem to be the lucky owner of a very good and very sharp copy of that faster zoom. Moreover, I fail to understand the comments about flare with this lens (even if normal), maybe I just do not understand or have become too used to it with the 20-40mm, where it can be quite heavily obvious at times. Not seen it yet on this 12-24mm, maybe it´s just the swiss importer doing a very good selection job up front. I´ll post a few samples as soon as I can, that is when finished setting up the galery on smugmug. Not for tomorrow, there´s a 400+ to sort out for last sunday alone...

On the negative side: that bulging front element gives me some nightmares in handling it! The other day, I almost posed it on a more or less flat wall to change lenses, as usual upside down, the hood becoming its feet; as always when changing lenses. Then I realized which lens I was holding, that the wall wasn´t exactly a wall, nor more or less flat (more a ridge on a rocky stretch), and I could stop my hand just in time. Just... Sweating a lot... It comes with the design though, and as such it has no influence on build rating.

- Nice size and weight
- Solid construction
- Virtually no distortion making it great for architecture
- Full Frame compatible.
Sharp from F8 onwards

negative:

Rear filters, front filtering possible but can cause vignetting, especially on full frame

comment:

I upgraded to this lens from the Sony 11-18mm mainly as I wanted to do more architecural photography and all reports indicated that this lens produced virtually zero linear distortion. I also wanted a super-wide that I could use with my Dynax7 and a future full frame D-SLR; the Sigma 12-24 is the only full-fraem zoom at this focal length.

So far it's everything I expected and has solved all the problems I had with the 11-18, namely distortion, corner sharpness and CA.

It can be a little soft upto F8 as widley reported in reviews, but is extremely sharp by F11 which suits me fine for landscape and architectural photography. You need to take care with point light sources and direct sunlight as it's very easy to get flare but that's to be expected at this focal length.

The lens takes rear-mount gelatin filters which I have not used as yet. an 82mm forward filter can be used thanks to the 2-piece lens cap but you will get some corner vignetting at 12mm on APS-C sensors, and much more serious on full frame.

Overall, the lens is a delight and I do not regret selling the 11-18mm.

[update 16.3.09]

Having owned this lens for a little while now, I've had plenty of oppertunity to put it through it's paces. The potential for lens flare takes a bit of getting used to and makes you think a little more when composing your shot; a good thing in my opinion.

It's definately soft wide open, improves around F8 and is much better by F11. It does soften up again beyond F16. For what I bought the lens for (architecture) it's fine. On the subject of architecture, the lack of lens distortion is a godsend saving heaps of time correcting in post.

Somewhat stiff zooming. But I'm used to it ... it's a Sigma trademark, of sorts. Also vignetting at the wide end ONLY when the lens cap/ filter holder is attached.

comment:

This is an excellent lens for what I do ... which is mainly indoor photography. At 12mm (18mm, APS-C), this lens literally ingests an entire room in one gulp. At 24mm (36mm, APS-C), it's just about right for close-up, head-on shots. In short, this is a great indoor walk-around lens.

This lens comes equipped (new) with a slide-on attachment that not only retains the lens cap, but also accomodates an 82mm filter; so I am not understanding the complaints of others in this area.

This lens is my newest sweetheart! I banished my Sigma 24-70DG 2.8 into my kitbox. My only regret is that I waited so long to get it.

-Too soft on both sides of the full frame Alpha 900, looks ok on Alpha 700 APC images.

comment:

On the Alpha 900, the image is very soft on the edges. This lens did no better when choking down the aperture unlike the Zenitar 16mm. Zooming in to 12mm or out to 24mm still yielded very soft edges. I am no expert, but I would estimate 5-6 blur units at least for the far right/left 10% of the image. Not acceptable.

It looks much better on the Alpha 700 where the soft edges are just outside the APC-C frame. I suspect many of those who get this lens for future-proofing might be in for a disappointment when they look at this lens on a full frame camera.

I sent the first back to BHP photo RMA for exchange, I will update this post when I get the replacement.

The front element of this beast is so big that it is impossible to use filter, i dont need a protective filter because i always take care of my glasses (and i believe you will too!), especially if they cost around 700 usd. But i gave a 5 because it is designed as what it is, and that means having a big bulging piece of glass in front, and to put a filter screw would make the filter sooo big to avoid vignetting, so it is understandable in my opinion, hence the 5. (AND it IS built like a tank - but treat it like a baby)
The other problem is that this glass display the typical sigma yellow/reddish colour cast, makes your pics somewhat warmer, BUT it is not without solution, just control with the WB, and presto!. Still, the colour contrast could be better.

The great thing about this glass is that the distortion is virtually negligible. On the edge wide open on APS-C it is somewhat sharper than the kit lens edge sharpness @18mm stopped down to 5.6, and that is quite impressive.
The AF on the 7D indoor at around EV 6-8 is fast, and accurate, so that is also impressive.
Flare control, simply put, from a lens with 12mm FF coverage, and had a big piece of glass the size of a tennis ball bulging in front of it, it has some problems. MOST NOTABLY, in strong flare situations, it produces a dominantly-blue-toned flare, which could pose problems in some situations.

Only 2 things differentiate this lens with the 10-20EX DC

-the 12-24 give only 92 deg. fov on APS-C the 10-20 give 102deg. BUT this thing has the ability to go FF, and THAT means better futureproofing, and 122deg. fov.
-This thing won't let you use cpol filter, and protective filter, the 10-20 has that ability
-this thing is heavier, bigger, and cost more than its little brother (OK, so that's three...)

I bought this lens because I wanted something wider and with less distortion than the kit lens. The Sigma provides this in a nice package, rugged build and a fine image quality. Regarding the WA I think flare control is quite good and distortion control is impressive.

However for €685 I expect to get something better than the cheap sigma lens cap that you can't grab in the centre. And the fact that the focus ring doesn't decouple also is a nuisance, it's close enough to the zoom ring to accidentally grip it when in AF.

Update: I sold this lens some time ago, I just didn't like the colour it produced. Also build quality wasn't up to the price. I've decided not to buy Sigma anymore.

good quality built
non-signifiacative distortion for this type of lens

negative:

flare
little bit "soft"
be careful with front lens !!!

comment:

Very good zoom !
A little bit soft with digital camera A700 , and very sensible compared to the 16-80 Zeiss in same conditions ...
No big diference of softness with film camera (Dynax 9xi).
The diference beetween sigma 12-24 and 20 Min AF "old" is not very significative ; better sharpness with 2,8/20 and better contrast ,but not so important !!!
be careful with flare of 12-24 !!! very sensible and contrast fell down with it !!!
That was a very good surprise testing this zoom ,because I hesitated with the famous 10-20 sigma.
I prefered buy this zoom for it's compatibility with film cameras or FF digital cameras ...

This lens is one of my workhorses and renders very good IQ with modest distortion even at 12mm for this type of lens. The flare control, even at 12mm is very good but is to be expected (this is a very bulbous lens) - after shooting hundreds of images at 12mm I have only had this problem on a handful of shots. I am a bit nervous using it because of the inability to give it protection via a filter coupled with its shape which is conducive to attracting dust and debris.

The quality of this lens is good, but not very good. After talking to many photographers I think this lens is at present the best wide angle zoom for Minolta/Sony.

I hope Zeiss will built a Lens which is realy a great wide angle lens.

Addendum:
Today I tested the Tamron 14 mm F 2,8 VS the Sigma 12-24. What a surprise. I thought the Tarmon would be better. But no way!!! The Sigma is definitely the better lens. The sharpness is 1 or 2 classes better, particularly with regard to the edges of the pictures.